Gravel packing is the technique of depositing proppant or sand in perforations to promote production and to slow the production of particulates from the formation as the hydrocarbons are produced. In the case of unconsolidated formation with relatively high permeability, much of the fluid used to circulate the gravel can be absorbed by the formation when gravel is delivered. To compensate for this fluid loss and to be able to also frac the formation as the gravel is delivered, the pumping rate has been greatly stepped up. While operations in more consolidated formations could result in an adequate frac job with about 15 barrels a minute flow rate, flow rates in the order of 65 barrels per minute or more are not unusual when dealing with a fairly unconsolidated formation.
In a typical installation, the gravel slurry is delivered down the tubing and goes through a packer and into a cross-over and into an inner annulus. The slurry from there has to make a radial exit due to the equipment configuration to get to the outer annulus that is the wellbore. If the well is cased at that point the slurry exit velocities at the higher pumping rates required in unconsolidated formations has in the past caused erosion problems where the slurry makes initial impact after exiting the openings from the inner annulus, as illustrated in FIG. 4. Additionally, if the well is open hole, the high fluid velocities make the filter cake on the wellbore wall come off. This is also not desirable as the gravel and fluid would tend to go into the formation at that location rather than further along the wellbore. Alternatively the filter cake can plug the gravel pack and impede subsequent production.
The present invention addresses the harm from high pumping rates of gravel slurry in unconsolidated formations by deflecting the exiting gravel flow away from the casing or borehole wall to reduce or eliminate the erosive effects from high impact of slurry. The deflection device also acts to improve impingement angles downstream which also can reduce the erosion of the casing or the removal of filter cake in open hole. The deflecting device is simple to fabricate and takes the brunt of the erosion effects from high velocity slurry impinging it. These and other aspects of the present invention can be more readily understood from a review of the description of the preferred embodiment that appears below along with the associated drawings. The claims at the end of the application are understood to define the full scope of the invention.